Disclosure of Invention
The technical problem to be solved by the invention is as follows: the method comprises the steps of establishing an affine nonlinear model of a telescopic boom recovery device, designing a high-interference-rejection docking control method by adopting a linear active interference rejection technology (LADRC) based on the model, so that accurate control of docking motion of the telescopic boom under disturbance of a space-based recovery environment is realized, and reliability and recovery efficiency of space-based recovery of the unmanned aerial vehicle are improved.
The invention adopts the following technical scheme for solving the technical problems:
the control method is realized based on a telescopic boom type unmanned aerial vehicle empty foundation recovery device, the device comprises a fixed platform arranged at the tail of an aircraft cabin of an empty foundation recovery platform, the lower end of the fixed platform is connected with a rotating base, the rotating base is connected with a boom through a controllable pitching joint, the boom is hollow and sleeved with a telescopic boom, the length of the telescopic boom is smaller than that of the boom, and a manipulator is arranged at the extending tail of the telescopic boom; the control method comprises the following steps:
step 1, establishing a yaw, pitch and telescopic joint coordinate system according to the structure and the freedom of motion of a telescopic arm type unmanned aerial vehicle space-based recovery device;
step 2, dividing a telescopic sleeve arm dynamic model into a yaw joint dynamic equation, a pitch joint dynamic equation and a telescopic joint dynamic equation according to different joint motion effects, constructing the yaw joint dynamic equation by adopting a rotational inertia mass projection method, and constructing the pitch and telescopic joint dynamic equations by adopting a Lagrange equation method;
step 3, forming a three-channel dynamic model of the telescopic sleeve arm by yaw, pitch and telescopic joint dynamic equations, and carrying out affine nonlinear processing on the three-channel dynamic model under the condition of considering environmental turbulence to obtain the three-channel affine nonlinear model of the telescopic sleeve arm;
step 4, aiming at the system lumped disturbance formed by the undetectable transient disturbance and the space-based recovery environment disturbed flow in the telescopic sleeve arm three-channel affine nonlinear model in the step 3, constructing an extended state observer to reconstruct the lumped disturbance of each channel;
and 5, combining the extended state observer in the step 4, designing a space-based recovery docking controller of the telescopic sleeve arm unmanned aerial vehicle based on a linear active disturbance rejection technology, and realizing space-based recovery docking control of the telescopic sleeve arm unmanned aerial vehicle under the environment disturbance flow.
As a preferable embodiment of the present invention, in the step 1, the yaw joint coordinate system is O0-X0Y0Z0Origin of coordinates O thereof0The yaw joint coordinate system is coincided with the center of the rotating base, the direction of a Z axis is coincided with the direction of a rotating shaft of the rotating base, an X axis is parallel to an X axis of a flight path coordinate system of the air-based recovery platform airplane, a Y axis is parallel to a Y axis of the flight path coordinate system of the air-based recovery platform airplane, and the yaw joint coordinate system meets the right-hand rule;
coordinate system of pitch joint is O1-X1Y1Z1Origin of coordinates O thereof1The direction of the Z axis is the direction of a rotating shaft of the controllable pitching joint, the direction of the X axis points to the telescopic direction of the telescopic arm, and the direction of the Y axis is determined according to a right hand rule;
coordinate system of telescopic joint is O2-X2Y2Z2Origin of coordinates O thereof2Is positioned at the center of the tail end of the sleeve arm, and the axial directions of the sleeve arm and the coordinate system of the pitching jointThe corresponding axes are parallel in direction and same in direction.
As a preferred scheme of the present invention, in step 2, a rotational inertia mass projection method is adopted to construct a yaw joint dynamic equation, which specifically includes:
in the formula, m1、m2、m3、m4The mass of the rotary base, the sleeve arm, the telescopic arm and the manipulator are respectively; r1、R2、R3Respectively the section radiuses of the rotating base, the sleeve arm and the telescopic arm; xi is the sleeve arm and X0Z0A plane included angle; omega1The yaw rate of the telescopic boom; delta is a sleeve arm and X0Y0A plane included angle; l2The length of the sleeve arm; l3The length of the telescopic arm; Δ l3The telescopic arm extends out of the sleeve arm by the length; tau is1Is yaw joint drive torque;
in the step 2, the pitching and stretching joint kinetic equations are obtained by means of a Lagrange equation according to a modeling method of the multi-joint mechanical arm under the condition that the interaction force in the system is not obtained, and the pitching and stretching joint kinetic equations are specifically as follows:
in the formula, ω
2Is the pitch angle speed of the telescopic sleeve arm; chi is the position of the mass center of the rigid body formed by combining the manipulator and the telescopic arm,
τ
2pitch joint drive torque; f
3Is the driving force of the telescopic joint; g isAcceleration of gravity; v. of
3The sliding speed of the telescopic arm is adopted;
K
3=(m
3+m
4)。
as a preferable scheme of the present invention, in step 3, under the condition that the space-based recovery environment turbulence is considered, the three-channel dynamic model of the telescopic boom is rewritten into an affine nonlinear form by using equivalent mathematical transformation, so as to obtain an affine nonlinear model of the telescopic boom, where the affine nonlinear model of the telescopic boom has a specific form as follows:
in the formula, X1=[ξ δ Δl3]T、X2=[ω1 ω2 v3]TAll are telescopic boom system states; b ═ diag (B)1,b2,b3)、U=[τ1 τ2 F3]TRespectively is an input matrix and a control input of the telescopic boom system; f ═ 0F2 f3]TIs an undetectable transient disturbance within the model; w ═ W1 w2 w3]TRecovery of environmental turbulence for empty foundation, w1=0.25ρCdR2V2(l2+Δl3)2sin2δsinξ,w2=0.5ρCdR2V2(l2+Δl3)2cosξsin3δ,w3=0.5ρΔl3CdR3V2cos ξ sin2 δ, where ρ, CdV is air density, drag coefficient and flight speed of the air-based recovery platform airplane respectively; d ═ D1 D2 D3]TLumped disturbance, D, of the system formed by the immeasurable transient disturbance in the model and the disturbance of the space-based recovery environment1、D2、D3Lumped disturbances are provided for yaw, pitch and flex channels, respectively.
As a preferred scheme of the present invention, in step 4, for a system lumped disturbance formed by an undetectable transient disturbance and a space-based recovery environment disturbed flow in a three-channel affine nonlinear model of a telescopic boom, a specifically constructed expansion state observer is as follows:
in the formula (I), the compound is shown in the specification,
are all estimated values of the state of the system,
is xi, delta and delta l respectively
3The value of the estimated value is,
respectively yaw angular velocity omega
1Pitch angle velocity omega
2And the sliding velocity v of the telescopic arm
3An estimated value; e.g. of the type
E=[e
E1 e
E2 e
E3]
TEstimating the deviation for the observer state, e
E1、e
E2、e
E3Estimating deviations for states of the yaw, pitch and telescopic channel observers respectively;
in order to provide a system with a global disturbance estimate,
respectively estimating the total disturbance of the yaw, the pitch and the telescopic channels;
are all the coefficients of the observer,
respectively the bandwidth of the three channel observer.
As a preferable scheme of the invention, in the step 5, the specific form of the air-based recovery docking controller of the telescopic boom unmanned aerial vehicle is as follows:
in the formula (I), the compound is shown in the specification,
in order to provide a telescopic boom state instruction,
respectively indicating yaw, pitch and telescopic channel state instructions; e.g. of the type
c1=[e
c11 e
c12 e
c13]
T、e
c2=[e
c21 e
c22 e
c23]
TAre systematic tracking errors, e
c11、e
c12、e
c13Yaw, pitch and telescoping channel tracking errors, respectively, e
c21、e
c22、e
c23Respectively differentiating the tracking errors of the yaw, the pitch and the telescopic channel; u shape
c=[u
c1 u
c2 u
c3]
TFor control input, u
c1、u
c2、u
c3Respectively as yaw, pitch and telescopic channel control inputs; c
1=diag(c
11,c
12,c
13)、C
2=diag(c
21,c
22,c
23) As controller coefficient, c
11、c
21For yaw channel controller coefficients, c
12、c
22For pitch channel controller coefficients, c
13、c
23Is the controller coefficient of the telescopic channel.
Compared with the prior art, the invention adopting the technical scheme has the following technical effects:
the invention provides a telescopic boom type unmanned aerial vehicle air-base recovery butt joint control method based on LADRC, a telescopic boom three-channel affine nonlinear model is constructed, and a model foundation is laid for the subsequent development of air-base recovery telescopic boom motion control design. And aiming at the influences of environment turbulence and immeasurable transient disturbance in the model in the space-based recovery process, a three-channel extended state observer is designed, and the immeasurable lumped disturbance of the system is accurately reconstructed. Meanwhile, an interference observation technology is combined, the telescopic sleeve arm type unmanned aerial vehicle air base recovery butt joint controller based on LADRC is provided, the motion control precision and the anti-interference capability of the telescopic sleeve arm are effectively improved, and the efficiency and the reliability of air base recovery are remarkably improved.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
The invention discloses a LADRC-based telescopic boom type unmanned aerial vehicle empty base recovery docking control method, which comprises the following steps of firstly, establishing a telescopic boom nonlinear model and carrying out affine nonlinear processing on the telescopic boom nonlinear model; furthermore, the influence of environment disturbed flow and undetectable transient disturbance in the model on the telescopic sleeve arm is comprehensively considered, and an extended state observer is designed to accurately reconstruct the undetectable concentrated disturbance in the system; then, estimating disturbance based on the extended state observer, and designing a high-disturbance-rejection butt joint control method of the space-based recovery telescopic boom based on a linear active disturbance rejection technology so as to realize accurate butt joint control of the telescopic boom under the environment disturbance flow.
In this example, a parent machine with a telescopic boom attached thereto is set to perform a constant level flight motion, with a flight height H of 3000m, a flight speed V of 100m/s, a mass of 136000kg, and a wing span of 39.88 m.
As shown in fig. 1, the method for controlling the air-based recovery and docking of the telescopic arm type unmanned aerial vehicle based on the LADRC specifically comprises the following steps:
step one, establishing a yaw, pitch and telescopic joint coordinate system according to the structure and the freedom of motion of the telescopic armlet type empty base recovery device shown in the figure 2.
The telescopic sleeve arm type empty base recovery device mainly comprises a rotating base 3, a controllable pitching joint 4, a sleeve arm 5, a telescopic arm 6 and a manipulator 7, and is integrally installed at the tail of a machine body of a mother machine 1 through a fixed platform 2. Wherein, the rotating base 3 and the controllable pitching joint 4 are driven by a hydraulic device, and the yawing and pitching movement of the telescopic arm can be realized. Meanwhile, the sleeve arm 5 is hollow inside, and the telescopic arm 6 is nested and installed to realize telescopic movement of the recovery device. And the manipulator 7 is used for grabbing and locking the unmanned aerial vehicle 8 to be recovered in the empty base recovery process.
In the established joint coordinate system, O0-X0Y0Z0The yaw joint coordinate system is a yaw joint coordinate system, a coordinate origin of the yaw joint coordinate system is coincided with the center of the rotating base, the direction of a Z axis is coincided with the direction of a rotating shaft of the rotating base, an X axis and a Y axis are respectively parallel to an X axis and a Y axis of a flight path coordinate system of the parent machine, and the whole coordinate system meets the right-hand rule; o is1-X1Y1Z1The system is a pitching joint coordinate system, a coordinate origin of the system is superposed with the center of a controllable pitching joint, the Z-axis direction is the direction of a rotating shaft of the pitching joint, the X-axis direction points to the telescopic direction of a telescopic arm, and the Y-axis direction is determined according to a right-hand rule; o is2-X2Y2Z2The telescopic joint coordinate system is characterized in that the coordinate origin is located at the center of the tail end of the sleeve arm, and the axial directions of the coordinate origin are parallel to the axial directions of the pitching joint coordinate system and have the same direction;
describing the motion state of the manipulator by means of the homogeneous transformation relation of the coordinate systems of all joints, and establishing a kinematic model of the telescopic boom0Pe:
In the formula:1Pethe position of the center of mass of the manipulator under a pitching coordinate system is shown;0T1a transformation matrix between a pitching coordinate system and a yawing coordinate system; l2The length of the sleeve arm; Δ l3The telescopic arm extends out of the sleeve arm by the length; delta is a sleeve arm and X0Y0A plane included angle; xi is the sleeve arm and X0Z0A plane included angle;
in this step, the length l of the arm is selected2=8.7m。
Dividing a telescopic sleeve arm dynamic model into a yaw part and a pitch-telescopic part according to different joint motion effects, and respectively constructing by adopting a rotational inertia mass projection method and a Lagrange equation method;
in the step, the dynamic equation of the yaw joint of the telescopic sleeve arm drives the whole telescopic sleeve arm to rotate around the rotating base because the yaw joint mainly moves, so that the dynamic model can drive the torque tau by the joint1Angular velocity omega of telescopic sleeve arm1And moment of inertia I1However, because the sleeve arm, the telescopic arm and the tail end manipulator have a certain included angle with the yaw motion rotating shaft, the corresponding rigid body moment of inertia needs to be obtained through a mass projection method. The telescopic boom pitching and telescopic joint dynamic equations can be obtained by means of a Lagrange equation under the condition that the interaction force in the system is not obtained according to a modeling method of the multi-joint mechanical arm. The yaw, pitch and telescopic joint dynamic model is as follows:
in the formula: m is
1、m
2、m
3、m
4The mass of the rotary base, the sleeve arm, the telescopic arm and the manipulator are respectively; r
1、R
2、R
3Respectively the section radiuses of the rotating base, the sleeve arm and the telescopic arm; l
3The length of the telescopic arm; omega
2Is the pitch angle speed of the telescopic sleeve arm; tau is
2Pitch joint drive torque; v. of
3The sliding speed of the telescopic arm is adopted; f
3Is the driving force of the telescopic joint; g is the acceleration of gravity;
the center of mass position of the rigid body is combined by the mechanical arm and the telescopic arm;
K
3=(m
3+m
4)。
and step three, forming a three-channel dynamic model of the telescopic sleeve arm by yaw, pitch and telescopic joint dynamic equations, and rewriting the three-channel dynamic model into an affine nonlinear form by adopting equivalent mathematical transformation under the condition of considering environmental turbulence. The specific form of the telescopic boom affine nonlinear model is as follows:
in the formula: x1=[ξ δ Δl3]T,X2=[ω1 ω2 v3]TAll are telescopic boom system states; b ═ diag (B)1,b2,b3),U=[τ1 τ2 F3]TRespectively is an input matrix and a control input of the telescopic boom system; f ═ 0F2 f3]TIs an undetectable transient disturbance within the model; w ═ W1 w2 w3]TRecovery of environmental turbulence for empty foundation, w1=0.25ρCdR2V2(l2+Δl3)2sin2δsinξ,w2=0.5ρCdR2V2(l2+Δl3)2cosξsin3δ,w3=0.5ρΔl3CdR3V2cos ξ sin2 δ, where ρ, CdV is air density, drag coefficient and aircraft flying speed; d ═ D1 D2 D3]TLumped disturbance, D, of the system formed by the immeasurable transient disturbance in the model and the disturbance of the space-based recovery environment1、D2、D3Lumped disturbances are provided for yaw, pitch and flex channels, respectively.
In the step, the mass of the rotary base, the mass of the sleeve arm, the mass of the telescopic arm and the mass of the manipulator are respectively m1=30kg,m2=250kg,m3=170kg,m425 kg; the section radiuses of the rotary base, the sleeve arm and the telescopic arm are respectively R1=0.15m,R2=0.1m,R30.08 m; length l of telescopic arm38.3 m; the gravity acceleration g is 9.8; air density ρ 0.73kg/m3(ii) a Coefficient of wind resistance Cd0.2; the flying speed V of the mother aircraft is 100 m/s.
Step four, aiming at system lumped disturbance formed by three-channel immeasurable transient model disturbance of the telescopic sleeve arm and space-based recovery environment disturbance in the step three, respectively constructing an extended state observer, and reconstructing the lumped disturbance of each channel;
in the step, aiming at system lumped disturbance formed by three-channel undetectable transient model disturbance of the telescopic sleeve arm and disturbance of the space-based recovery environment, the constructed expansion state observer specifically comprises the following steps:
in the formula:
are all estimated values of the state of the system,
is xi, delta and delta l respectively
3The value of the estimated value is,
respectively yaw angular velocity omega
1Pitch angle velocity omega
2And the sliding velocity v of the telescopic arm
3An estimated value; e.g. of the type
E=[e
E1 e
E2 e
E3]
TEstimating the deviation for the observer state, e
E1、e
E2、e
E3Estimating deviations for states of the yaw, pitch and telescopic channel observers respectively;
in order to provide a system with a global disturbance estimate,
respectively estimating the total disturbance of the yaw, the pitch and the telescopic channels;
are all the coefficients of the observer,
respectively the bandwidth of the three-channel observer;
in this step, the bandwidths of the three-channel observers are respectively selected as
And step five, combining the extended state observer in the step four, providing a telescopic arm type unmanned aerial vehicle air-based recovery docking controller based on LADRC.
The specific form of the controller used in the LADRC-based telescopic boom docking control method in the step is as follows:
in the formula:
in order to provide a telescopic boom state instruction,
respectively indicating yaw, pitch and telescopic channel state instructions; e.g. of the type
c1=[e
c11 e
c12 e
c13]
T、e
c2=[e
c21 e
c22 e
c23]
TAre systematic tracking errors, e
c11、e
c12、e
c13Yaw, pitch and telescoping channel tracking errors, respectively, e
c21、e
c22、e
c23Respectively differentiating the tracking errors of the yaw, the pitch and the telescopic channel; u shape
c=[u
c1 u
c2 u
c3]
TFor control input, u
c1、u
c2、u
c3Respectively as yaw, pitch and telescopic channel control inputs; c
1=diag(c
11,c
12,c
13),C
2=diag(c
21,c
22,c
23) As controller coefficient, c
11、c
21For yaw channel controller coefficients, c
12、c
22For pitch channel controller coefficients, c
13、c
23Is the controller coefficient of the telescopic channel.
In this step, the specific control coefficient of the controller is selected as C1=diag(60,50,70);C2=diag(80,70,90)。
By adopting the LADRC-based air-based recovery and docking control method for the telescopic boom type unmanned aerial vehicle, the initial state of the telescopic boom is
The target state is
Under the condition of (3), the observer and the butt joint control result are obtained through simulation.
As shown in (a), (b) and (c) of fig. 3, the linear extended state observer lumped disturbance estimation result is designed for this example. According to the diagram, although the yaw, pitch and collective disturbance of the telescopic sleeve arm are changed rapidly in the recovery and butt joint process, the designed observer can still track the real disturbance well and the estimation deviation is small. Therefore, it is fully demonstrated that the linear extended state observer provided by the invention has a good estimation effect on lumped disturbance of each channel in the telescopic boom space-based recovery process.
Fig. 4-5 are simulation result diagrams of the telescopic boom docking control method provided by the invention. As can be seen from (a), (b) and (c) in FIG. 4, each channel of the telescopic boom can better track the docking instruction under the control of the designed controller, and the tracking error of the whole process is small. Meanwhile, as can be seen from fig. 5, the movement of each joint of the telescopic sleeve arm is well matched in the recovery and butt joint process, and the butt joint track is smooth. Therefore, the telescopic boom butt joint control method provided by the invention is verified to still have a good control effect and high anti-interference capability under the action of environmental turbulence.
The above embodiments are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modifications made on the basis of the technical scheme according to the technical idea of the present invention fall within the protection scope of the present invention.